Predation from intestinal amoebae may provide selective pressure for the maintenance of high genetic diversity at the Salmonella enterica rfb locus, whereby serovars better escape predators in particular environments depending on the O-antigens they express. Here, the hypothesis that amoebae from a particular intestinal environment collectively prefer one serovar over another is tested. Collections of Acanthamoeba, Tetramitus, Naegleria and Hartmannella were isolated from the intestinal tracts of several vertebrate hosts, including bullfrog tadpoles, goldfish, turtles and bearded dragons, and their feeding preferences were determined. Congeneric amoebae from the same environment had significantly similar feeding preferences. Strikingly, even unrelated amoebae – such as Naegleria and Tetramitus from goldfish – also had significantly similar feeding preferences. Yet amoebae isolated from different environments showed no similarity in prey choice. Thus, feeding preferences of amoebae appear to reflect their environment, not their taxonomic relationships. A mechanism mediating this phenotypic convergence is discussed.
BoydE. F.,
WangF.-S.,
BaltranP.,
PlockS. A.,
NelsonK.,
SelanderR. K.1993; Salmonella reference collection B (SARB): strains of 37 serovars of subspecies I. J Gen Microbiol 139:1125–1132[CrossRef]
EckburgP. B.,
BikE. M.,
BernsteinC. N.,
PurdomE.,
DethlefsenL.,
SargentM.,
GillS. R.,
NelsonK. E.,
RelmanD. A.2005; Diversity of the human intestinal microbial flora. Science 308:1635–1638[CrossRef]
GordonD. M.,
CowlingA.2003; The distribution and genetic structure of Escherichia coli in Australian vertebrates: host and geographic effects. Microbiology 149:3575–3586[CrossRef]
GordonD. M.,
BauerS.,
JohnsonJ. R.2002; The genetic structure of Escherichia coli populations in primary and secondary habitats. Microbiology 148:1513–1522
HeinrichsD. E.,
YethonJ. A.,
WhitfieldC.1998; Molecular basis for structural diversity in the core regions of the lipopolysaccharides of Escherichia coli and Salmonella enterica. Mol Microbiol 30:221–232[CrossRef]
HolstO.,
BradeH.1992; Chemical structure of the core region of lipopolysaccharides. In Bacterial Endotoxic Lipopolysaccharides pp 134–170 Edited by
MorrisonD. C.,
RyanJ. L.
Boca Raton, FL: CRC Press;
HoskingS. L.,
CraigJ. E.,
HighN. J.1999; Phase variation of lic1A, lic2A and lic3A in colonization of the nasopharynx, bloodstream and cerebrospinal fluid by Haemophilus influenzae type b. Microbiology 145:3005–3011
JenningsM. P.,
HoodD. W.,
PeakI. R. A.,
VirjiM.,
MoxonE. R.1995; Molecular analysis of a locus for the biosynthesis and phase-variable expression of the lacto- N -neotetraose terminal lipopolysaccharide structure in Neisseria meningitidis. Mol Microbiol 18:729–740[CrossRef]
KnirelY. A.,
KocharovaN. A.,
BystrovaO. V.,
KatzenellenbogenE.,
GamianA.2002; Structures and serology of the O-specific polysaccharides of bacteria of the genus Citrobacter. Arch Immunol Ther Exp (Warsz) 50:379–391
LeroyA.,
De BruyneG.,
MareelM.,
NokkaewC.,
BaileyG.,
NelisH.1995; Contact-dependent transfer of the galactose-specific lectin of Entamoeba histolytica to the lateral surface of enterocytes in culture. Infect Immun 63:4253–4260
LeyR. E.,
PetersonD. A.,
GordonJ. I.2006; Ecological and evolutionary forces shaping microbial diversity in the human intestine. Cell 124:837–848[CrossRef]
MilkmanR.,
JaegerE.,
McBrideR. D.2003; Molecular evolution of the Escherichia coli chromosome. VI. Two regions of high effective recombination. Genetics 163:475–483
PalmerC.,
BikE. M.,
EisenM. B.,
EckburgP. B.,
SanaT. R.,
WolberP. K.,
RelmanD. A.,
BrownP. O.2006; Rapid quantitative profiling of complex microbial populations. Nucleic Acids Res 34:e5[CrossRef]
RobbeC.,
CaponC.,
FlahautC.,
MichalskiJ. C.2003; Microscale analysis of mucin-type O-glycans by a coordinated fluorophore-assisted carbohydrate electrophoresis and mass spectrometry approach. Electrophoresis 24:611–621[CrossRef]
RobbeC.,
CaponC.,
CoddevilleB.,
MichalskiJ. C.2004; Structural diversity and specific distribution of O-glycans in normal human mucins along the intestinal tract. Biochem J 384:307–316[CrossRef]
RonnR.,
McCaigA. E.,
GriffithsB. S.,
ProsserJ. I.2002; Impact of protozoan grazing on bacterial community structure in soil microcosms. Appl Environ Microbiol 68:6094–6105[CrossRef]
StanleyC. M.,
PhillipsT. E.1999; Selective secretion and replenishment of discrete mucin glycoforms from intestinal goblet cells. Am J Physiol 277:G191–G200
van PuttenJ. P.1993; Phase variation of lipopolysaccharide directs interconversion of invasive and immuno-resistant phenotypes of Neisseria gonorrhoeae. EMBO J 12:4043–4051
WangL.,
RomanaL. K.,
ReevesP. R.1992; Molecular analysis of a Salmonella enterica group E1 rfb gene cluster: O-antigen and the genetic basis of the major polymorphism. Genetics 130:429–443
WildschutteH.,
WolfeD. M.,
TamewitzA.,
LawrenceJ. G.2004; Protozoan predation, diversifying selection, and the evolution of antigenic diversity in Salmonella. Proc Natl Acad Sci U S A 101:10644–10649[CrossRef]